Snowboards are somewhat similar to surfboards in appearance and riding style. They are used to ride on snow rather than surf. A snowboard has a tip or "shovel", a central contact zone, and a tail. The outer sides of boards capable of easily carving turns through the snow have sidecuts, giving the boards a slight hourglass configuration. The base of the snowboard is typically similar to that of snow skis, with steel edges circumscribing the outer shape of the base. A rider stands substantially sideways on the board with his feet skewed toward the shovel of the board. The rider applies pressure to the side of the board corresponding to the desired direction of turn. This causes the board to tilt into the snow on edge and the shovel and tail of the board to flex upwardly relative to the midrunning surface. The radius of curvature of the tilted edge (the "turning edge") causes the board to carve a turn.
Because of the wide running surface of snowboards riders may have difficulty properly tilting a board on edge to carve a turn. To avoid toe or heel drag when turning on edge, the midsection width of the board is approximately equal to the length of the boots of a rider. The shovel and tail are somewhat wider. One approach to overcoming the difficulty in tilting the board to edge is using a narrower board and skewing the feet further to avoid toe or heel drag. However, this approach is limited by the rider's desire to have a substantially sideways stance. The average preferred foot angle from directly sideways is about 27 degrees.
One attempt to provide a narrower base to help a rider to more easily edge, while still avoiding toe or heel drag, is disclosed in U.S. Pat. No. 5,018,760 to Remondet. The Remondet snowboard has an upper portion substantially as wide as the rider's boots are long and a significantly narrower (110 mm narrower) lower portion projecting well below (7 to 8 mm below) the bottom surface of the upper portion. With this narrower running surface the rider can tilt the board to initiate a turn on the narrower base with less force. If the rider continues to tilt the board he can ride on both the inner and outer edges or on the outer edge only. The Remondet board, while being easier to tilt, suffers from snow accumulation between the upper and lower portions. This tends to make the board skid as edge control is lost, especially when tilting the board from an inner to an outer edge. The Remondet configuration also increases friction between the board and the snow surface due to height of the sidewalls of the narrower base. Constructing a board in the configuration taught by Remondet results in a thick board that is too rigid to properly flex for carving. Also, the narrowness of the lower portion of the board and the resulting high angle between the upper and lower portions results in overtracking and makes the board unstable when landing after a jump.
Remondet also teaches that the outer configuration of the board is to be asymmetric for proper force application to the sidecuts, due to a skewed foot stance. However, the skewed upward curvature of the shovel creates a problem. When varying snow conditions, bumps, or depths are encountered, the skewed shovel tends to kick the front of the board in a toe-side direction, which is disconcerting to the rider because it upsets the rider's balance.
As another approach to help overcome edging difficulty, some boards have a slightly convex base (i.e., the base along the longitudinal centerline of the running surface is slightly lower than the edges). This allows the rider to slightly "rocker" the board for smoother edge-to-edge transitions.
While convex bases may be one solution to the difficulty of edging, they create other problems. Convex-based snowboards tend to skid or slide sideways before the edge is fully set, cutting rider speed and control. The board is sloppier since the edges don't bite as readily into the snow. Also, straight-line stability is greatly sacrificed.
An ideal snowboard should maximize the desired advantageous characteristics of the convex base for edge-to-edge board tilting to the outer edges to carve turns, while eliminating the skidding that takes place before a convex base board is tilted enough to firmly set the outside edges. Additionally, poor straight-line stability, inherent in the convex-based boards, should be improved. This invention is directed to providing such a board.